The present invention relates to a method for diagnosing the prognosis of damaged animal tissues, including human tissue by detection of an electric current flow through the tissue. The invention relates to a method and procedure for measuring, recording and analyzing the electrical field in and around areas of a living body and in particular the method identifies and defines a discrete electrical profile of a wound during a healing, worsening or stopped condition.
Electrophysiology is the science and branch of physiology that delves into the flow of ions in biological tissues, the electrical recording techniques which enable the measurement of this flow and their related potential changes. One system for such a flow of ions is the Power Lab System by ADInstruments headquartered in Sydney, Australia.
Clinical applications of extracellular recording include among others, the electroencephalogram and the electrocardiogram. To understand these biomedical signals, it is necessary to understand signal types, properties and statistics.
Deterministic signals are exactly predictable for the time span of interest. Deterministic signals can be described by mathematical models. Stochastic or random signals are those signals whose value has some element of chance associated with it, therefore it cannot be predicted exactly. Consequently, statistical properties and probabilities must be used to describe stochastic signals. In practice, biological signals often have both deterministic and stochastic components.
Regarding signal amplitude statistics, a number of statistics may be used as a measure of the location or “centre” of a random signal. These include,                The mean, which is the average amplitude of the signal over time.        The median, which is the value at which half of the observations in the sample have values smaller than the median and half have values larger than the median. The median is often used as the measure of the “centre” of a signal because it is less sensitive to outliers.        The mode, which is the most frequently occurring value of the signal.        The maximal and minimal amplitude, which are the maximal and minimal value of the signal during a given time interval.        The range or peak-to-peak amplitude, which is the difference between the minimum and maximum values of a signal.        
Regarding continuous time signals versus discrete time signals, signals are continuous time signals when the independent variable is continuous, therefore the signals are defined for a continuum of values of the independent variable X(t). An analogue signal is a continuous time signal. Discrete time signals are only defined at discrete times; the independent variable takes on only a discrete set of values X(n). A digital signal is a discrete time signal.
A discrete time signal may represent a phenomenon for which the independent variable is inherently discrete (e.g., amount of calories per day on a diet). On the other hand, a discrete signal may represent successive samples of an underlying phenomenon for which the independent variable is continuous (e.g., a visual image captured by a digital camera is made of individual pixels that can assume different colors).
There are quantitative methods to measure the frequency and amplitude of a waveform. One of the most well known is called spectral analysis: any waveform can be mathematically decomposed in a sum of different waveforms. This is what the so-called Fourier analysis does; it decomposes the waveform in different components and measures the amplitude (power) of each frequency component. What is plotted is a graph of power (amplitude) vs. frequency.
Whereas research on direct current (DC) activity in wound healing and tissue remodeling has a long history, electric fields of alternating current (AC) with specific frequencies have been much less studied.
Specific frequencies have been detected in various biological pathways known to be associated with wound healing such as pain, cell metabolism inter-cellular communication and bone growth. However, due to the absence of suitable measurement tools, there has been no definitive proof of involvement of AC with defined frequency spectra in wounds.
Further, to date no diagnostic method based on a discrete electrical profile that provides a prognosis for wound healing has been ventured in the medical filed.
There is therefore a need for a diagnostic method that identifies and defines a discrete electrical profile of a wound during a healing, worsening or stopped condition so as to provide a prognosis for such wounds. It would be beneficial if the method is linked to an appropriate electrical pulse transmission device in order to monitor and adjust the electrical therapy applied to damaged tissue based on the measured electrical field of the relevant tissues of the body.